SYDNEY (Reuters) - A China-born academic has been forced out of a leading Australian university for posting online politically charged remarks about his countrymen, re-igniting accusations Beijing is using its presence inside global campuses to exert soft power.

University of Sydney business school tutor Wei Wu, who gave up his Chinese citizenship to be Australian last year, quit earlier this week ahead of a university investigation into his conduct. Chinese students had complained he used racist language in a heated exchange on social media, prompting the probe.

In his argument with students on social media website Weibo, Wu, 26, called Chinese students in Australia "tun" in Mandarin, a word for pig which, according to his supporters, is also slang for rich, young Chinese who flout their devotion to communism abroad. In postings over the past year, he also published footage of himself burning his Chinese passport, the supporters said.

The tutor's supporters told Reuters the complaint originated with a student group affiliated with the Chinese consulate in Sydney, a sign that they said suggested the complaint was intended to stifle anti-Beijing rhetoric.

"There is a line between whether he's been abusive to students and whether he has a right to freedom to express himself on a topic which is widely discussed," said Wai Ling Yeung, the China-born former head of Chinese studies at Curtin University, who wrote a second petition calling for the university to protect Wu's freedom of speech.

In her petition, Yeung wrote that Chinese Australians are concerned Wu is becoming a victim of Chinese government attempts to curb voices of dissent among overseas Chinese.

The Chinese consulate in Sydney and the Chinese embassy did not immediately respond to email enquiries. The Sydney University Chinese Student & Scholar Association, which Wu's supporters said filed the petition, did not respond to a telephone message requesting comment.

The University of Sydney business school is a liberal institution with "limited control over external organizations and the influence they may or may not exercise over groups of students", Deputy Dean John Shields said in an email to Reuters.

He said a question about whether the business school takes instructions from Chinese government interests was "inappropriate, based on a false premise and does not warrant a response".

Wu did not respond to an email request seeking comment.

CULTURE POWER

The matter sparked a debate on social media, including posts of satirical images of the university with photoshopped banners from Tiananmen Square, the site of a 1989 student massacre, saying "long live the People's Republic of China".

Since 2004, China has established hundreds of "Confucius Institute" cultural centers on campuses around the world and started paying scholarships to thousands of its nationals studying abroad, raising concerns among some academics that universities are becoming too dependent on the financial benefit to keep mainland politics out.

The matter is particularly sensitive in Australia, where state-financed universities are cutting less profitable courses to cope with funding cuts while expanding others seen as popular with full-fee-paying foreign students.

In 2015, China provided a third of the country's record 272,095 foreign university students, government data shows. Chinese students pumped about A$5 billion ($3.9 billion) into the economy, according to standard estimates of how much foreign students spend.

"It's more about political dissidence or different views about Chinese culture," said Yonglin Chen, a former Chinese diplomat who defected to Australia in 2005, referring to the university's censuring of Wu.

"It's pressure because (the university is) worried about the Chinese education market."